Question: What is the uncertainty that corresponds to tritium, which has a mass excess of 14949.8?
Paraphrase: Which is the uncertainty that corresponds to tritium, which has a mass excess of 14949.8?
SPARQL (Wikidata): SELECT ?value WHERE { wd:Q54389 p:P2160 ?s . ?s ps:P2160 ?x filter(contains(?x , '14949.8')) . ?s pq:P2571 ?value}